Liquid used for soil treatment in applications of fertilizers, herbicides, pesticides and other soil treatments is often applied to the ground surface by spraying from an elongated boom moved over the field surface behind a tractor. The liquid is fed to the boom from a container either carried on the spraying device or otherwise attached to the tractor. The boom is typically mounted in a transverse orientation to the direction of movement to the tractor in order to produce a wide application pattern. The overall length of the boom enables application of the liquid in a minimum number of passes or swaths across the field. The difficulty, however, is in knowing exactly where the boundary of the previous liquid application swath lies since it is desirable to avoid overlapping applied liquid, or leaving areas or gaps of ground surface untreated.
Various forms of foam marking devices have been developed as suggested solutions to the above problem. Such devices usually include a relatively complex mechanism for mixing components to produce a foam marker that is discharged at one end of a spray boom to mark the boundary of the spray pattern. These apparatus are functional but are quite complex and, consequently, expensive. Furthermore, the foam components are not readily available.
One example of a foam marking device for liquid applicators is disclosed in U.S. Pat. No. 3,481,545 to Cooke et al. Cooke et al discloses a pressurized foam producing apparatus for selectively discharging patches of foam at opposed ends of a spray discharge boom. The foam material itself is not specifically disclosed but merely is indicated as being an "agriculturally unobjectionable foamable liquid". The apparatus requires a container for receiving the foamable liquid and for being pressurized by an air compressor or by other mechanism to produce the foam and to discharge it by delivery tubes to the liquid applicator boom ends.
U.S. Pat. No. 3,531,024 to Rosselot discloses an electrically operated field marking device by which a spray marker is applied to the boundary of a liquid spray pattern. The marking substance is indicated as being a powder such as dehydrated lime.
Other apparatus have been used for physically marking the ground surface by means of a cutting disk. U.S. Pat. Nos. 3,903,970; 3,072,200; 3,766,987; and 3,524,508 disclose such apparatus. Use of this form of apparatus is not feasible in previously planted fields since the marking device will destroy a portion of the crop.
Disposable paper streamers have been utilized in aircraft for marking the boundaries of a treatment area of the ground surface in which the treatment has been applied by aircraft. One example of such is found in U.S. Pat. No. 3,470,846. This patent shows a magazine carrying a plurality of independent streamers for individual discharge through an end of the magazine. The device makes use of air pressure directed into the magazine to feed the individual markers toward the rear opening. A plunger is utilized to separate the rearmost streamer from the remainder of the stack for discharge to the ground surface.
U.S. Pat. No. 4,316,554 discloses another form of aerial marker launcher using individual elongated strips.
The problem of marking treated areas of the ground surface is also recognized in smaller applications. For example, U.S. Pat. No. 3,443,727 to Wellford discloses a lawn marker for use in conjunction with a dry granular or powdered material dispenser. This device makes use of an auxiliary wheel mounted to the frame of the spreader. The wheel is filled with a marking material that is discharged in small amounts on each rotation of the auxiliary wheel. The small amount of discharged material therefore produces a spot or dot positioned along the boundary of the area being treated.
Another example of a somewhat similar device is disclosed in U.S. Pat. No. 3,019,470. Here, however, the marking material is applied directly to the ground surface from nozzles situated ahead of the cart wheels. An integral hopper for marking the boundary of applied material in a similar lawn spreader is shown in U.S. Pat. No. 3,198,383. This hopper is formed integrally with the material hopper of the spreader and delivers its marking material through the available spreading mechanism.
U.S. Pat. No. 2,199,421 discloses a liquid marking device mountable to seed planters. A liquid marking medium is delivered by hoses to opposed ends of the seed planter unit and is discharged to the ground surface for marking the seeding swath at its outward borders.
Of the above references, none provide a simple yet adequate solution to the problem of marking the boundaries of treated ground surface. Devices applying liquid markers often employ dyes, paint, or other materials that are not easily distinguishable from a distance. Often such materials are harmful to the soil and not readily available to the user.
Foam markers are perhaps more visible, yet the foaming agents are not readily available and the foam producing equipment is complex and expensive.
Powder markers have the drawback of potential permanence. For example, a lime deposit used as a marker will remain on the ground surface until plowed under. This could cause confusion if subsequent applications of liquid need be applied. The previous markers could be confused with present markers.
Tissue markers offer a viable alternative but until the present invention, have not been available for ground operated implements or with the marking medium in a readily available form. Former tissue streamers are specially constructed with tissue strips attached to cardboard dividers and nested in a stack for dispensation from an airplane. This special construction is required by the dispensing apparatus for proper operation. The tissue strips, due to their unique construction, are not readily available on the market.
Even so, tissue markers are desirable since the paper components readily disintegrate into the soil after a short period with no ill effects to the surrounding vegetation. Thus, while the advantages of tissue used as field markers has been recognized, the problem of adequately applying readily available tissue markers from ground supported liquid applying apparatus has not been recognized or adequately solved until the advent of the present invention.
The present invention is provided as a solution to the above problems by facilitating application of a readily available paper tissue to the ground surface as a field marker from a ground supported implement. The marking apparatus is specially adapted to remove sections from readily available roll of tissue paper, thus providing a simple and effective solution to the problem of quick and inexpensive access to an adequate marking medium.